The present invention is directed to mounting arrangements for knives and coulter wheel assemblies which are sometimes used in the application of anhydrous ammonia. The knife and coulter are supported by and connected to portable tool bars. Numerous arrangements of this general type are shown in the prior art U.S. Pat. Nos., 2,722,902, 2,849,969, 2,924,187, 3,237,577, 3,296,985, 3,306,241, 3,410,234, 3,469,637, 3,745,944, 3,752,092, 3,799,079, 4,538,532 and 4,574,715. Problems have been encountered with these arrangements. When the soil is rocky, it is necessary to allow the coulter to pivot about the vertical shank on which it is mounted to prevent damage to the coulter. The prior art devices result in a side load on the knife when turns are made or an obstacle is struck often resulting in bending or breaking of the knife.